<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<style>
    .box{
        background-color: blue;
        width: 200px;
        height: 200px;
        margin: auto;
    }
</style>
<body>
    <div class="box">2</div>
    <script>
        function fn(){
            let arr=['1','2','3','4','5','6','7','8','9','a','b','c','d','e','f']
            let str='#'
            for(let i=0;i<6;i++){
                str+=arr[Math.floor(Math.random()*16)]
            }
            return str;
        }
        function fn(){
            let q=Math.floor(Math.floor(Math.random()*256))
             let w=Math.floor(Math.floor(Math.random()*256))
              let e=Math.floor(Math.floor(Math.random()*256))
              return`rgb(${r},${g},${b})`
        }
        
        
       



    </script>
</body>
</html>